racemic N-acylated α,α-disubstituted amino acids were resolved by coupling to chiral amines 15-18 derived from (S)-phenylalanine to form diastereoisomers 19/20 or 21/22 that could be separated by crystallization and/or flash chromatography on silica gel (Scheme 3). Selective cleavage via the 1,3-oxazol-5(4H)-ones 10a-p gave the corresponding optically pure α,α-disubstituted amino-acid derivatives 11 or
This invention is directed to tetrahydronaphthalene compounds of the formula ##STR1## wherein R.sup.1 is hydrogen, bromine, cyano, formyl, hydroxy, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, aryloxy, lower aralkoxy or aryl; R.sup.2 is an amino acid residue or a chain of 2 to 20 amino acid residues wherein reactive moieties in the side chains of the amino acid residue(s) is/are protected or unprotected, and wherein the amino group of the N-terminal amino acid is a free or protected amino group; A.sup.1, A.sup.2, A.sup.3 and A.sup.4 each are .alpha.-amino acid residues wherein A.sup.1 and A.sup.2 are in the L configuration and A.sup.3 and A.sup.4 are in the D configuration when the .alpha.-C atom of said .alpha.-amino acid residue is asymmetric; X is oxygen or sulphur; Y is a residue of the formula ##STR2## n is 0 or 1; R.sup.3 is hydrogen or lower alkyl; R.sup.4 is hydrogen or lower alkyl; and Z and the two C atoms together are an aromatic ring selected from the group of benzene, furan, thiophene, pyridine or pyrimidine, wherein said aromatic ring is substituted or unsubstituted; and salts thereof and their intermediates. The compounds are useful as mimetics of exposed helical domains of proteins in order to clarify their role with respect to interactions with other proteins or with DNA or RNA through .alpha.-helical conformation. They are therefore valuable aids in the determination of biologically active peptide sequences and are accordingly so-called "research tools". They are also potentially useful as medicaments.
The present invention is concerned with tetrahydronaphthalene derivatives which are mimics of domains of peptides or proteins which can interact with other proteins or with DNA or RNA through .alpha.-helical conformation, said tetrahydronaphthalene derivatives having the formulae: ##STR1## are valuable aids in the determination of biologically active peptide sequences and are accordingly so-called "research tools". They are, however, also potentially suitable as medicaments.
structures are described (Figs. 1–4), showing β-turn type-I geometries for dipeptides 4a, 5b, and 4c and an extended conformation for peptide 5c (Table 3). The conversion of the free amino acids 1a–c into suitably protected building blocks 11a–d and 15d,e for peptidesynthesis is discussed (Schemes 3 and 4).